In a small warehouse in Arden Hills, he and three co-owners have taken the craft brewery model and tweaked it for vintage pop, the Pioneer Press reported .

Northern Soda Co., which opened in July, is set up like the old Pop Shoppe stores, inviting customers to assemble their own packs of pop from pallets in the 38,000-square-foot warehouse. Instead of getting a 12-pack of cream soda, for example, a customer could choose 12 different flavors, among them Ginger Pop, Mango Citrus and Sunday Purple.

The company has 85 recipes in its collection, but features only 10 to 12 flavors at a time, cycling them with the seasons.

It’s a return to a time when drinking soda was a unique treat.

Hopkins, who is a child of the ’80s, remembers his dad taking him and his sisters to the Pop Shoppe to pick out their flavors. He was allowed one soda per week, so he would save his for Sunday so he could drink it watching football.

“We want people to drink our sodas and remember what it was like for them as a kid,” Hopkins said. “We want to provide our customers with a product that stirs up nostalgia.”

To that end, the cans have a colorful retro design.

Hopkins didn’t just fashion his style after the old-time soda shop; he kept with the simple ingredients of the time — cane sugar, water, flavor and a touch of citric acid. A few have food coloring and a dab of food preservative, but not much.

“We don’t use extra preservatives,” he said. “We don’t intend for them to sit around on a shelf for two years.”

He uses non-GMO ingredients and many of his drinks are non-caffeinated and free of sodium and gluten. But he’s not touting them as health food.

“At the end of the day, it is a soda,” he said.

Sometime around 1984, the big soda companies switched out cane sugar for high-fructose corn syrup and started putting soda in plastic bottles, two moves Hopkins feels ruined the flavor he’d grown to love.

“I cannot drink any soda out of a plastic bottle,” he said.

Breweries made the same mistake with beer, he said, favoring the bottom line over the purity of the flavor, which is why craft breweries have been so successful.

A home craft brewer himself, he approached the pop craft with the same critical standards brewers use.

“We consider the smell and the mouth feel and the last flavor that’s in your mouth,” he said. He puts a little cinnamon in the root beer, a touch of vanilla in the cola and a hint of citrus in the strawberry to leave the tongue intrigued. He also lightens up on the carbonation because, he said, too many bubbles mess with the taste.

Hopkins has been a teacher and assistant principal for 17 years. In fact, he and his co-owners — Davod Zarghami, Tom Schlehuber and Michael Goodwin — are all current or former educators, as are their wives.

Hopkins and Zarghami work full-time at the business and the other two still have their school jobs. Schlehuber is a science teacher at Heritage E-STEM Magnet School in West St. Paul, and Goodwin is a middle school counselor in Pine Island, Minn.

As a hobby, Hopkins dabbled in beer brewing but made carbonated beverages for his kids and friends who didn’t drink alcohol. He studied the craft brewery industry and thought about going in that direction, but decided to take a chance with vintage pop, a market not yet saturated in Minnesota, he said.

His first endeavor was Whistler Classic Soda, which he ran for five years. That company tried to mimic the Pop Shoppe model by using real glass bottles. He even bought a massive 1950s mint-green bottling machine that took up most of his floor space in the Whistler building, a former auto shop in Forest Lake.

He sold the business in 2016 when he was offered an assistant principal job at Heritage, where Schlehuber teaches. Hopkins and his wife, Julie, live in White Bear Lake with their five children. While he says he loved working with students, his decision to sell was something he regretted instantly.

“It was just gnawing at me the whole time,” he said. “I really missed the creative side and the pure happiness that soda is.”

In May 2018, he talked with his partners about starting another specialty-soda company. He’d learned a lot with the Whistler experiment and had two years to think about all the things he’d do differently.

First change: Ditch the glass bottles. They look cool, but they don’t preserve the flavor like an aluminum can does. Plus, they’re heavy and can’t go everywhere (like beaches and stadiums), and the bottling machine was a massive menace to run. He likes his small, portable canning machine much better.

“It’s tiny. It’s on wheels. It can be moved around,” he said.

The pop is mixed in 90-gallon batches and then moved to a chilling tank, where it’s combined with carbon dioxide and chilled to 33 degrees. After resting for 24 hours, it’s ready to be canned. The cans, which are fitted with a sleeve decorated by a designer in Barcelona, are sanitized, filled and capped. A quick rinse and they’re ready to move to the pallet.

Second change: Get partners who can market and sell the product so the company doesn’t fizzle out.

“I ran Whistler by myself. I was doing everything. I didn’t have the time to spend on marketing, or even just thinking about what a marketing plan should look like. I had a great product, but people didn’t know about it,” he said.

His partners, who bring their own skill sets to the table, have helped Northern Soda grow much faster than Whistler did, he said.

Their projected profit margin for their first year in operation is $300,000, with hopes to eventually expand. They’ve acquired 87 retail customers, including Hy-Vee and Kowalski’s grocery stores. They sell online, too. Hopkins recently shipped a crate to a customer in Hawaii. Craft breweries such as 3rd Act in Woodbury like having a soda selection for their younger customers.

Having help gives Hopkins the time to do what he loves best, coming up with new flavors like strawberry habanero, huckleberry and cardamom.